1. Field of the Invention
The present invention relates to a wire antenna, and more particularly to a small wire antenna applied to wireless communication devices.
2. Description of the Prior Art
With the improvement of wireless network technology, a user can use wireless network anytime and anywhere. The antenna structure in wireless network technology is often designed that an antenna and a grounding element are integrated as a same element. An inverted F type antenna has been extensively applied in particular.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of an inverted F type antenna in the prior art. U.S. patent publication no. 20070296636A1 discloses a planar antenna, which is the inverted F type antenna structure operating in the 2.4 GHz band.
In FIG. 1, a main radiating element A is smaller than a grounding element B. Owing to a grounding plane made of a metal, it increases size and cost of an antenna. However, wireless network terminal devices tend towards miniaturization and portable designs by user request, and internal antenna designs also tend towards miniaturization accordingly.
The inverted F type antenna is only capable of operating in a single band in present wireless network technology. Therefore, the conventional inverted F type antenna can not achieve requested dual-band operation. However the mainstream of electronic products tends towards dual-band operation in wireless network technology.